Goop is a thicker product than gluvit and it has a fiber mixed in to help fill small cracks and holes. Gluvit is much thinner and made to run into tiny recesses and around rivets. Most folks choose gluvit for the inside and if they want an exterior coating then go with goop. If your exterior is in good shape, just gluvit inside and a good enamal outside. The goop is thick enough it won't run into the tiny spaces and get around all the rivets as well as the gluvit. Your call, your boat....just puttin my two cents out there...
